There would be instances where in different scenario , there would be difference in speed of accessing Backend Server while load balancing the traffic through NetScaler.

First Instance: If the user is trying to access the Backend Server if the traffic is crossing the MPLS Traffic.

Second Instance : If the user is trying to access the Backend Server if there are Firewalls and Routers in the traffic Flow and VPN is getting terminated on any of the Firewall/Routers.



 

Troubleshooting the First Instance and Second Instance:

First take the simultaneous captures on all the intermediate device and NetScaler also.
If the first point is not feasible, take the captures only on NetScaler.
If grepping the captures are still not valid on NetScaler, by-pass NetScaler and compare the speed of the same.
If after by-passing NetScaler, it seems to be same speed/time to fetch the resources, then take take the captures individually on Router / Switch / Firewall involved in accessing the traffic.

P.S : Kindly contact the concerned device TAC for resolving the slowness issue soon.